How to choose a compost product
The look, feel and smell are the best first indicators. Good compost:
- Has a medium – to dark-brown color and a crumbly texture.
- It is not too wet or dry and may feel warm, but it should not be hot.
- A mild, sweet, earthy odor indicates good maturity.
- Avoid compost with a strong rotten-egg or ammonia smell.
What about possible contaminants?
- It is uncommon for commercial compost to have significant herbicide or pesticide residues, weed seeds or plant diseases because of the way it is processed in large facilities.
- Heavy metals are uncommon, except sometimes in compost made from biosolids (sewage waste).
- Salts are a little more common – particularly in compost made from manures or food wastes – but are generally less of a problem, especially when the compost is applied when rains can wash salts from the soil.